JavaScript creator and current CTO of Mozilla Corporation Brendan Eich provides a detailed history of JavaScript, including some of the more interesting programs written with JavaScript, right up to how JavaScript has been essential to the Ajax or Web 2.0 revolution.
Eich started work on JS in 1995 and says he's been surprised by how popular it has been: "I was resigned for a long time to JS being unpopular due to those annoying popups, but more: due to its unconventional combination of functional and prototype-based object programming traditions."
And with multicore/massively-parallel computers upon us, Eich talks about the future of JavaScript: "JS has its role to play in addressing the multicore world, starting with relatively simple extensions such as Google Gears' worker pools -- "shared nothing" background threads with which browser JS communicates by sending and receiving messages."

I really like javascript as a language. The biggest problem, though, is Internet Exploder, whose implementation of Javascript is unspeakably poor, and really spoils it for me. Of course, that's probably what Microsoft intended....

So use a toolkit like Dojo to abstract out the IE vs. Rest-Of-The-World issues.